This invention relates to an optical pick-up device, and more particularly to an optical pick-up device used for irradiating light beams onto an optical disc caused to undergo rotational operation to carry out recording of information signals onto the optical disc, or to carry out reproduction of information signals recorded on the optical disc.
Hitherto, optical pick-up devices used for carrying out recording of information signals with respect to an optical disc, or for reproducing information signals recorded on the optical disc includes an object lens (objective) for converging light beams emitted from light source to irradiate them onto signal recording surface of the optical disc, and is further provided with a movable portion for allowing the object lens to undergo drive displacement in a focusing direction in parallel to the optical axis thereof and in a tracking direction of plane direction perpendicular to the optical axis, and a fixing portion for supporting this movable portion. The movable portion includes drive coils, i.e., focusing coil and tracking coil.
In this case, in order to allow the object lens to undergo drive displacement in the focusing direction and in the tracking direction so that light beams focus on the signal recording surface of the optical disc to follow recording tracks, it is necessary to deliver, from the external, drive currents corresponding to focusing error signal and tracking error signal to the drive coils constituting the movable portion.
As the optical pick-up device adapted for delivering current from the outside of the device to the drive coils of the movable portion, there are optical pick-up devices as shown below.
An optical pick-up device 101 shown in FIGS. 1 and 2 comprises a movable portion 107 in which printed wiring boards for connection 106, 106 are attached at a lens holder 105 which has held an object lens 102, a focusing coil 103 and tracking coils 104, 104. This movable portion 107 is supported so that it is permitted to undergo displacement in a direction in parallel to the optical axis of the object lens 102 and in a plane direction perpendicular to the optical axis through four suspensions 110 having bottom end portions supported by a fixing portion 108 and connected to a printed wiring board 109 for external connection supported at the fixing portion 108. By soldering front end portions of the four suspensions 110 which have displaceably supported the movable portion 107 and end portions of the focusing coil 103 and the tracking coils 104 with respect to the printed wiring boards for connection 106, 106, supporting with respect to the fixing portion 108 of the movable portion 107 and electrical conduction to the outside of the device of the respective coils 103, 104, 104 are realized.
Moreover, in an optical pick-up device 201 shown in FIGS. 3 and 4, there are provided in a projected manner (hereinafter simply referred to as projected as occasion may demand) plural coil binding projections 206 at a lens holder 205 which has held an object lens 202, a focusing coil 203 and plural tracking coils 204 to constitute a movable portion 207 to bind end portions of the respective coils 203 and 204 with respect to predetermined coil binding projections 206 to solder thereat front end portions of four suspensions 210 having bottom end portions supported by a fixing portion 208 and connected to a printed wiring board 209 for external connection supported by the fixing portion 208 to realize supporting with respect to the fixing portion 208 of the movable portion 207 and electric conduction to the device outside of the respective coils 203, 204.
Meanwhile, in the optical pick-up device 101 shown in FIGS. 1 and 2, it is necessary to provide printed boards 106 for connection. As a result, the number of parts is increased. Further, space for providing the connection printed boards 106 is required. Thus, not only weight of the device itself is increased, but also the device itself becomes large sized. Further, since the connection printed board 106 is attached at the lens holder 105 by, e.g., adhesive agent, there results lowered responsibility resulting from change with passage of time of adhesive agent. In addition, there occurs increase in the number of assembling steps. This might also give the cause to increase production cost.
Further, the optical pick-up device 201 shown in FIGS. 3 and 4 requires projections like coil binding projections 206 at the lens holder 205. Thus, miniaturization is prevented as the result of the fact that such projections are provided. In addition, working for binding end portions of the coils 203, 204 at the coil binding projections 206 is required. These results the increased number of assembling steps. This also constitute the cause that the manufacturing cost is increased.
An object of this invention is to provide a novel optical pick-up device which can solve the technical problems that the conventional optical pick-up devices have.
Another object of this invention is to provide an optical pick-up device which can reduce the number of parts, and realize light weight and miniaturization.
In the optical pick-up device according to this invention proposed in order to attain such objects, a movable portion in which drive coil is provided at a lens holder of synthetic resin for holding an object lens is supported at a fixing portion having magnet opposite to the drive coil through suspensions doubling as electric current supply medium from external circuit. Further, conductive portions formed by the resin plating method are provided at the lens holder to solder end portion of the drive coil and one ends of the suspensions to the conductive portions to realize supporting with respect to the fixing portion of the movable portion and electric connection with respect to an external circuit of the drive coil.
In accordance with this optical pick-up device, the end portion of the drive coil and one ends of suspensions are soldered to the conductive portion integrally provided at the lens holder so that supporting with respect to the fixing portion of the movable portion and electric connection with respect to the external circuit of the drive coil are realized. Accordingly, the number of parts is reduced and miniaturization of the device itself is realized. In addition, since reduction in the number of parts is realized, the number of assembling steps is reduced. Thus, reduction in the manufacturing cost can be realized.